The OSUCCC Analytical Cytometry Shared Resource (ACSR) is an extensive, institutionally-supported shared service. This core provides one of the only means of rapidly and accurately analyzing multiple characteristics of biological particles while also being able to rapidly, accurately, and with high purity (>98%) sort out pure populations of cells of interest based on parameters designated by the investigator. Furthermore, this service provides OSUCCC members with the ability to obtain viable, sterile and pure populations of cells so that they may be individually cloned, can be assessed for immunological function, or can be examined for specific biochemical properties with minimal manipulations, compared to magnetic bead technologies. This shared resource has five primary goals: 1) Provide state of the art flow cytometry analysis and sorting on a fee-for-service basis; 2) Provide individual training followed by 24-hour access to flow cytometry instrumentation for researchers who wish to conduct their own analysis; 3) Develop and provide educational and training opportunities for new and experienced resource users as well as forums to introduce new instrumentation, technologies and reagents to OSUCCC investigators; 4) Obtain and provide state-of-the-art equipment to support high quality cancer research for OSUCCC members; and 5) Introduce new, or pre-commercial, emerging technology to support high quality cancer research for OSUCCC members. The ACSR main facility is centrally located and has eight flow cytometry instruments, four of which are capable of sorting. Two flow cytometer analyzers are available for independent (24 hour access) and assisted analysis. In addition, commercial and prototype magnetic separation and analysis equipment is available. Five' of these instruments were purchased with institufional support of approximately $1,358,000 in the last four years. In order to meet the needs of heavy users and maintain adequate space and access, the ACSR has two satellite facilifies located in the James Cancer Hospital (JCH) and the OSU College of Veterinary Medicine (CVM). The CVM has three flow cytometers, one of which is equipped to safely sort virus infected cells. The ACSR Director is Jeffrey Chalmers, Ph.D. with a manager, Bryan McElwain, and two additional staff. The CVM satellite is managed by A. Nicole White and has an additional technician. In addition, this past year Mary Jo Burkhard, D.V.M., Ph.D. was recruited as a co-investigator in the ACSR focused on education and outreach. The ACSR continues to provide critical support to the investigators and scientific programs, including 14 clinical studies acfively using the services of the ACSR This past year, nearly 75% of the ACSR usage was from 63 CCSG peer-reviewed, funded OSUCCC investigators from all six programs who consumed over 4,300 hours of service, yet only 23.4% of the support came from the CCSG.